/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.analysis;

import java.util.Map;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import org.apache.lucene.analysis.CharStream;

/**
 * Factory for {@link PatternReplaceCharFilter}.
 * 
 * <pre class="prettyprint" >
 * &lt;fieldType name="text_ptnreplace" class="solr.TextField" positionIncrementGap="100"&gt;
 *   &lt;analyzer&gt;
 *     &lt;charFilter class="solr.PatternReplaceCharFilterFactory" pattern="([^a-z])" replacement=""
 *                 maxBlockChars="10000" blockDelimiters="|"/&gt;
 *     &lt;tokenizer class="solr.KeywordTokenizerFactory"/&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;
 * </pre>
 * 
 * @version $Id: PatternReplaceCharFilterFactory.java 1074023 2011-02-24
 *          02:25:08Z koji $
 * @since Solr 3.1
 */
public class PatternReplaceCharFilterFactory extends BaseCharFilterFactory {

	private Pattern p;
	private String replacement;
	private int maxBlockChars;
	private String blockDelimiters;

	@Override
	public void init(Map<String, String> args) {
		super.init(args);
		try {
			p = Pattern.compile(args.get("pattern"));
		} catch (PatternSyntaxException e) {
			throw new RuntimeException(
					"Configuration Error: 'pattern' can not be parsed in "
							+ this.getClass().getName(), e);
		}
		replacement = args.get("replacement");
		if (replacement == null)
			replacement = "";
		maxBlockChars = getInt("maxBlockChars",
				PatternReplaceCharFilter.DEFAULT_MAX_BLOCK_CHARS);
		blockDelimiters = args.get("blockDelimiters");
	}

	public CharStream create(CharStream input) {
		return new PatternReplaceCharFilter(p, replacement, maxBlockChars,
				blockDelimiters, input);
	}
}
